完善

src/app/babylon/game.ts

@@ -38,7 +38,10 @@ export class Game {
 
         // 监听浏览器改变大小的事件，通过调用engine.resize()来自适应窗口大小
         window.addEventListener("resize", function () {
-            Game.instance.engine.resize();
+            if (Game.instance != null) {
+                Game.instance.engine.resize();
+            }
+
         });
 
     }